JP2013224431A - Optical pressure-sensitive adhesive agent, and optical pressure-sensitive adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive agent which can form a pressure-sensitive adhesive layer good in adherence to an adherend, not causing foams at a pasted interface, not causing lifting and exfoliation, and not generating light leakage phenomenon, even if being exposed for a long period to high-temperature and high-humidity and the like after being pasted to an adherend, and being excellent in processability.SOLUTION: An optical pressure-sensitive adhesive agent contains 100 parts by weight of an acrylic polymer and 5 to 50 parts by weight of an isocyanate-based curing agent, wherein the acrylic polymer is a copolymer of monomers containing 10 to 100 wt.% of a monomer (A) capable of forming a homopolymer having an SP value of 10 to 18 (cal/cm)in 100 wt.% of the total of the monomers; and the acrylic polymer has a hydroxyl value of 0.05 to 5 mgKOH/g.

Description

  The present invention relates to an adhesive having good adhesion to an adherend such as glass and an optical adhesive sheet.

Display devices such as liquid crystal displays are used in various devices such as home appliances and commercial appliances such as electronic computers, electronic watches, mobile phones, and televisions. Especially, liquid crystal and plasma televisions are becoming larger. In recent years, it has also been used for in-vehicle devices such as car navigation, and is required to withstand severe conditions such as high temperature and high humidity.
In the display device, polarizing films and retardation films having various optical functions are used, and these are attached to an adherend such as glass through an adhesive.

  The polarizing film is a laminate having a configuration in which a polyvinyl alcohol film is sandwiched between a triacetyl cellulose film and a cycloolefin film. And since each said film has a different mechanical characteristic, the dimensional change rate at the time of a heating also differs, Therefore When it puts in a high temperature atmosphere, a curvature will arise in a laminated body in many cases.

  Therefore, for example, when a laminate composed of a polarizing film / adhesive layer / glass (of a liquid crystal cell) is placed under high temperature or high temperature and high humidity conditions, and the warp resulting from dimensional change occurs in the polarizing film, the adhesive layer and the glass There arises a problem that bubbles (foaming) are generated at the sticking interface, and that the polarizing film is lifted from the glass and peeled off. Also, the stress distribution of the laminate becomes uneven due to warpage, and as a result of stress concentration at the four corners of the laminate or at the peripheral edges, light leaks from the four corners and peripheral edges of the laminate, so-called The problem of “light leakage phenomenon” occurred.

Then, the proposal which tries to solve the said problem by adjustment of an adhesive composition is made.
A high molecular weight (meth) acrylic copolymer having a weight average molecular weight of 1 million or more, which is a copolymer of an alkyl (meth) acrylate and a polymerizable monomer having functionality for a crosslinking agent, and a weight average From a pressure-sensitive adhesive for a polarizing plate comprising a low molecular weight (meth) acrylic copolymer having a molecular weight of 30,000 or less and a polyfunctional compound having at least two functional groups capable of forming a crosslinked structure in the molecule, and the pressure-sensitive adhesive. A polarizing plate having a formed adhesive layer has been proposed (see Patent Document 1).

  The resin component includes (A) a (meth) acrylic acid ester homopolymer or copolymer having a weight average molecular weight of 500,000 to 2,000,000, and (B) a (meth) acrylic acid having a weight average molecular weight of 5,000 to less than 500,000. And a (meth) acrylic acid ester copolymer having a nitrogen-containing functional group in the molecule, wherein at least one of the component (A) and the component (B) includes an ester homopolymer or a copolymer. An adhesive is proposed (see Patent Document 2).

  Furthermore, a copolymer having a weight average molecular weight of 1,000,000 to 2,000,000, which is obtained by radical copolymerization of a monomer having a reactive functional group and another monomer, and a carboxyl group in the presence of the copolymer. A copolymer (B) having a weight average molecular weight of 10,000 or more and 100,000 or less, and the copolymer (A) and / or the copolymer ( B) an adhesive composed of a polyfunctional compound having at least two reactive functional groups capable of reacting with B), and an optical member in which an adhesive layer composed of the adhesive is formed on at least one surface of the optical member (See Patent Document 3).

Furthermore, a pressure-sensitive adhesive in which the gel fraction of the pressure-sensitive adhesive is adjusted using a pressure-sensitive adhesive composed of an alkyl (meth) acrylate copolymer, an antioxidant and a curing agent has been proposed (see Patent Document 4).
As a result, it was considered that the above problem was solved because the laminate did not cause foaming at the sticking interface, did not float or peel, and did not cause light leakage.
However, when the polarizing film is also enlarged with the enlargement of the TV screen, the dimensional change is also increased, and the pressure-sensitive adhesive described in Patent Documents 1 to 4 cannot relieve stress and cannot prevent light leakage. There has occurred. Furthermore, since the pressure-sensitive adhesive film described in Patent Documents 1 to 4 has a soft pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer protrudes from the end of the laminate, resulting in contamination of the surface of the polarizing film and reworkability. There was a problem of shortage and deterioration of workability.

  In view of this, a method has been proposed in which the adhesive strength of the adhesive is increased and the generated stress distribution is concentrated at the four corners and the peripheral edges to reduce the light leakage area and reduce the apparent light leakage. However, even the pressure-sensitive adhesive sheet using the pressure-sensitive adhesive could not achieve all the above problems.

JP-A-10-279907 JP 2001-89731 A JP 2004-331697 A JP 2003-49143 A JP 2008-292673 A

  The object of the present invention is good adhesion to the adherend, and after sticking to the adherend, even if it is exposed to high temperature and high humidity for a long time, foaming does not occur at the sticking interface, and it floats and peels off. It is another object of the present invention to provide a pressure-sensitive adhesive capable of forming a pressure-sensitive adhesive layer having excellent processability and an optical pressure-sensitive adhesive sheet.

The present invention contains 100 parts by weight of an acrylic polymer and 5 to 50 parts by weight of an isocyanate curing agent, and the acrylic polymer has a SP value of 10 to 18 (cal / cm) in a total of 100% by weight of monomers. ³ ) A monomer copolymer containing 10 to 100% by weight of monomer (A) capable of forming a ^1/2 homopolymer, wherein the acrylic polymer has a hydroxyl value of 0.05 to 5 mgKOH / g It is an optical pressure-sensitive adhesive characterized.

  Adhesion to the adherend is good according to the present invention, and even after being attached to the adherend and exposed to high temperature and high humidity for a long period of time, foaming does not occur at the attachment interface, and neither lifting nor peeling occurs. Furthermore, it was possible to provide a pressure-sensitive adhesive capable of forming a pressure-sensitive adhesive layer not only causing no light leakage phenomenon but also excellent in workability, and an optical pressure-sensitive adhesive sheet thereof.

It is important that the optical pressure-sensitive adhesive of the present invention contains 100 parts by weight of an acrylic polymer and 5 to 50 parts by weight of an isocyanate curing agent. And, it is characterized in that polyurea having a rigid skeleton is formed by self-condensation of an isocyanate compound in the presence of an acrylic polymer. And the optical pressure-sensitive adhesive sheet using the optical pressure-sensitive adhesive of the present invention has a very high cohesive force, so that the pressure-sensitive adhesive layer foams and floats even after being exposed to an environment such as high temperature and high humidity. The effect of not peeling off and causing the above light leakage phenomenon is exhibited.
Here, the acrylic polymer used in the present invention is preferably radically polymerized by solution polymerization, bulk polymerization, aqueous polymerization, emulsion polymerization, ultraviolet polymerization or the like, and particularly preferably solution polymerization.

The acrylic polymer preferably uses the monomer (A) as a raw material. Monomer (A) is a monomer whose homopolymer has an SP value of 10.0 to 18.0 (cal / cm ³ ) ^1/2 .
In the present invention, since the polyurea formed in the adhesive layer described later has a higher polarity than the acrylic polymer, the compatibility with the acrylic polymer is lowered during the polyurea formation process, and the adhesive layer may be whitened. Therefore, it is desirable to increase the polarity of the acrylic polymer in order to increase the compatibility with polyurea.

Therefore, by using the monomer (A) as a raw material, the polarity of the acrylic polymer can be increased, so that the compatibility with polyurea is high and whitening does not occur.
The monomer (A) is preferably used in an amount of 10 to 100% by weight, more preferably 15 to 100% by weight, and particularly preferably 20 to 100% by weight in the total 100% by weight of the monomers. If the amount used is less than 10% by weight, the compatibility of the acrylic polymer may be lowered because the polarity of the acrylic polymer is lower than that of polyurea. The SP value in the present invention is an abbreviation for a solubility parameter, and is calculated from the molecular structure of the compound by the Fedors method (described in POLYMER ENGINEERING AND SCIENCE, FEBRUARY, 1974, Vol. 14, No. 2 147-154). It is a numerical value.

The monomer (A) can be divided into a monomer containing no functional group and a monomer containing a functional group.
Examples of the monomer not containing the functional group include methyl acrylate, ethyl acrylate, benzyl (meth) acrylate, phenoxyethyl acrylate, glycidyl (meth) acrylate, 2-methoxyethyl acrylate, acrylonitrile, cyclohexyl acrylate, Examples thereof include styrene and vinyl acetate.
Examples of the monomer having a functional group include acrylic acid, methacrylic acid, β-carboxyethyl acrylate, itaconic acid, maleic acid, maleic anhydride, crotonic acid, fumaric acid, fumaric anhydride and the like carboxyl groups or acid anhydride groups. Containing monomer, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, (meth) acrylic acid 6 Hydroxyl group-containing monomers such as hydroxyhexyl, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, caprolactone-modified (meth) acrylic acid; glycidyl acrylate And epoxy such as glycidyl methacrylate Containing monomers; acrylamide, N- methylol acrylamide, an amide group-containing monomers such as N- methylol methacrylamide. Among these, methyl acrylate, ethyl acrylate, and 2-methoxyethyl acrylate are particularly preferable. One or more kinds of these monomers (A) can be used.

It is also preferable to use monomers other than the monomer (A) for the acrylic polymer of the present invention. Specific examples include (meth) acrylic acid alkyl ester monomers other than the monomer (A), styrene monomers, vinyl monomers, and the like.
Examples of the (meth) acrylic acid alkyl ester monomer include methyl methacrylate, ethyl methacrylate, propyl (meth) acrylate, iso-propyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylate iso. -Acrylic of linear or branched aliphatic alcohols such as butyl, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate And acid esters and corresponding methacrylic acid esters.
Examples of the styrene monomer include alkyl styrene such as methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene and octyl styrene.
Examples of vinyl monomers include conjugated diene monomers such as butadiene, isoprene and chloroprene.
These monomers can be used alone or in combination of two or more.

In the present invention, the acrylic polymer preferably has an acid value of 0.05 to 80 mgKOH / g, more preferably 0.1 to 70 mgKOH / g, and particularly preferably 0.5 to 60 mgKOH / g. Examples of the functional group having an acid value include a carboxyl group, a sulfonyl group, and a phosphoric acid group. These acid components accelerate the reaction of the isocyanate curing agent, and the curing proceeds rapidly. However, when the acid value is higher than 80 mgKOH / g, curing is too fast, and there is a possibility that coating property may be lowered and foaming may occur in the adhesive layer.
Here, the acid value in the present invention refers to the number of mg of potassium hydroxide required to neutralize free fatty acid, resin acid and the like contained in 1 g of acrylic polymer.

  Furthermore, the acrylic polymer of the present invention preferably has a hydroxyl value of 0.05 to 5 mgKOH / g, more preferably 0.1 to 3 mgKOH / g, and 0.15 to 2.0 mgKOH / g. Is particularly preferred. The hydroxyl group in the acrylic polymer reacts quickly with the isocyanate curing agent to become a stronger pressure-sensitive adhesive having a cross-linked structure, and the processability is improved. However, when the hydroxyl value is higher than 5 mgKOH / g, the degree of crosslinking is excessive, the flexibility of the acrylic polymer is lost, and the adhesion to the adherend may be reduced. In addition, the hydroxyl value in this invention means the mg number of potassium hydroxide required in order to neutralize the acetylation thing of the hydroxyl group contained in 1g of acrylic polymers.

Next, the isocyanate curing agent will be described.
The optical pressure-sensitive adhesive of the present invention needs to contain an isocyanate curing agent. Specifically, a compound containing a bifunctional or higher functional isocyanate group is preferable, and a compound containing a trifunctional or higher functional isocyanate group is more preferable.

  Examples of the compound containing an isocyanate group include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, tetramethylxylylene diisocyanate, naphthalene diisocyanate, triphenylmethane. Polyisocyanate compounds such as triisocyanate and polymethylene polyphenyl isocyanate, adducts and burettes of these isocyanate compounds and polyol compounds such as trimethylolpropane, isocyanurates, and also these isocyanate compounds and known polyether polyols Polyester polyol, acrylic polyol Le, polybutadiene polyols, adducts, etc. and polyisoprene polyol and the like.

  As the isocyanate curing agent used in the present invention, a trimethylolpropane adduct of tolylene diisocyanate, an isocyanurate of tolylene diisocyanate, and an isocyanurate of isophorone diisocyanate are preferable, and in particular, a trimethylolpropane adduct of tolylene diisocyanate. Is more preferable. Two or more of these may be used

In the present invention, the cohesive force of the pressure-sensitive adhesive layer is adjusted by adding 5 to 50 parts by weight of an isocyanate curing agent to the acrylic polymer, but the cohesive force can also be adjusted depending on the type of the isocyanate curing agent. Hexamethylene diisocyanate having a flexible skeleton, trimethylolpropane adduct or burette of the above diisocyanate can be added in an amount of 8 to 50 parts by weight, preferably 10 to 40 parts by weight, more preferably 12 to 30 parts by weight. .
Also, tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, tetramethylxylylene diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, polymethylene poly having a rigid skeleton. 5 to 40 parts by weight, preferably 7 to 30 parts by weight, and more preferably 9 to 25 parts by weight of the polyisocyanate compound such as phenyl isocyanate and the isocyanurate of the above isocyanate can be added. If the amount added is less than 5 parts by weight, the strength of the pressure-sensitive adhesive is insufficient, processability is reduced, and light leakage may occur. On the other hand, when the addition amount is more than 50 parts by weight, the cohesive force of the adhesive layer becomes excessive, the adhesion to the adherend is lowered, and there is a possibility that it may be lifted or peeled off.

  It is also preferable to use a curing agent other than the isocyanate curing agent in combination with the pressure-sensitive adhesive of the present invention. Specific examples include epoxy-based, ethyleneimine-based, metal chelate-based, and amine-based curing agents. By using these curing agents, the cohesive force of the pressure-sensitive adhesive becomes higher, and the light leakage phenomenon can be improved more effectively.

  Examples of the ethyleneimine curing agent include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxite), N, N′-toluene-2,4-bis (1-aziridinecarboxite). Bisisophthaloyl-1- (2-methylaziridine), tri-1-aziridinylphosphine oxide, N, N′-hexamethylene-1,6-bis (1-aziridinecarboxite), 2,2 ′ -Bishydroxymethylbutanol-tris [3- (1-aziridinyl) propionate], trimethylolpropane tri-β-aziridinylpropionate, tetramethylolmethanetri-β-aziridinylpropionate, Tris-2, 4,6- (1-aziridinyl) -1,3,5-triazine and the like can be mentioned.

  Examples of epoxy curing agents include bisphenol A-epichlorohydrin type epoxy resins, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol. Diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl aniline, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N′-diglycidylaminomethyl) Examples include cyclohexane, N, N, N ′, N′-tetraglycidylaminophenylmethane, and triglycidyl.

  Examples of metal chelate curing agents include coordination compounds of polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium and acetylacetone and ethyl acetoacetate. Can be mentioned.

Examples of the amine-based curing agent include hexamethylene diamine, triethyl diamine, polyethyleneimine, hexamethylene tetramine, diethylene triamine, triethyl tetramine, isophorone diamine, amino resin, and methylene resin.
These curing agents are preferably used in an amount of 0.01 to 10 parts by weight, more preferably 0.03 to 5% by weight, and particularly preferably 0.05 to 3% by weight with respect to 100 parts by weight of the acrylic polymer.
When the amount of other curing agent used is less than 0.01 parts by weight, the adhesive physical properties may not be further improved. On the other hand, if the amount exceeds 10 parts by weight, the degree of cross-linking becomes too high, the cohesive force of the adhesive layer becomes excessive, and the adhesion to the adherend is lowered, so that there is a risk of floating or peeling.

  The pressure-sensitive adhesive of the present invention preferably further contains an antistatic agent. Examples of the antistatic agent include metal compounds such as antimony pentoxide, tin oxide, zinc oxide, and indium oxide, complex metal compounds such as antimony-containing complex oxides, In-Sn complex oxides, and phosphorus compounds, Anionic surfactants such as quaternary ammonium salts, long-chain alkyl compounds having a sulfonate group, thiophene derivatives, polymers having an ionized nitrogen element in the main chain, sulfonate group-modified polystyrene, polyaniline, etc. Polymers, ionic liquids such as nitrogen-containing onium salts, sulfur-containing onium salts, and phosphorus-containing onium salts, alkali metal salts, alkaline earth metal salts, alkali metal salts of organic boron complexes, alkaline earth metal salts of organic boron complexes, etc. Is mentioned. Among these, ionic liquids and quaternary ammonium salts are preferable in terms of antistatic performance, compatibility with pressure-sensitive adhesives, and bleed-out resistance. The antistatic agent is preferably 0.001 to 20 parts by weight with respect to 100 parts by weight of the adhesive. More preferably, it is 0.01-15 weight part, Furthermore, 0.1-10 weight part is preferable. If the amount is less than 0.001 part by weight, the antistatic effect may be insufficient. If the amount exceeds 20 parts by weight, the antistatic agent may bleed on the surface of the pressure-sensitive adhesive, causing floating, peeling, foaming, cracking, etc. .

  The antistatic agent is an antistatic agent (B) comprising a compound represented by the following general formula (1), or an antistatic agent comprising an anion and a cation (C) represented by the following chemical formula (2). It is preferable to use these in combination.

General formula (1)

Wherein R ^{1 to} R ⁸ are each independently a hydrogen atom, an alkyl group that may have a substituent, an alkenyl group that may have a substituent, or an alkynyl group that may have a substituent. Represents an aryl group which may have a substituent, or a heterocyclic group which may have a substituent, and R ^{5 to} R ⁸ may form a ring with adjacent substituents.

Chemical formula (2)

R ¹ to R ⁸ of the compound represented by the general formula (1) in the present invention are each independently a hydrogen atom, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or a substituent. The alkynyl group which may have a group, the aryl group which may have a substituent, and the heterocyclic group which may have a substituent are represented.

  As the alkyl group which may have a substituent, an alkyl group having 1 to 30 carbon atoms is preferable, for example, methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group, decyl group, dodecyl group, Okudadecyl group, isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, 1-ethylpentyl group, cyclopentyl group, cyclohexyl group, trifluoromethyl group, 2-ethylhexyl group, phenacyl group, 1-naphthoylmethyl group 2-naphthoylmethyl group, 4-methylsulfanylphenacyl group, 4-phenylsulfanylphenacyl group, 4-dimethylaminophenacyl group, 4-cyanophenacyl group 4-methylphenacyl group, 2-methylphenacyl group, 3-fluorophenacyl group, 3-trifluoromethylphenacyl group, 3-ni Rofenashiru group, and the like.

  As an alkenyl group which may have a substituent, a C2-C10 alkenyl group is preferable, for example, a vinyl group, an allyl group, a styryl group etc. are mentioned.

  The alkynyl group which may have a substituent is preferably an alkynyl group having 2 to 10 carbon atoms, and examples thereof include an ethynyl group, a propynyl group, and a propargyl group.

As the aryl group which may have a substituent, an aryl group having 6 to 30 carbon atoms is preferable, and a phenyl group, a biphenyl group, a 1-naphthyl group, a 2-naphthyl group, a 9-anthryl group, a 9-phenanthryl group, 1-pyrenyl group, 5-naphthacenyl group, 1-indenyl group, 2-azurenyl group, 9-fluorenyl group, terphenyl group, quarterphenyl group, o-, m-, and p-tolyl group, xylyl group, o- , M-, and p-cumenyl group, mesityl group, pentarenyl group, binaphthalenyl group, turnaphthalenyl group, quarternaphthalenyl group, heptaenyl group, biphenylenyl group, indacenyl group, fluoranthenyl group, acenaphthylenyl group, aceanthrylenyl group, Phenalenyl group, fluorenyl group, anthryl group, bianthracenyl group, teranthra Nyl group, quarter anthracenyl group, anthraquinolyl group, phenanthryl group, triphenylenyl group, pyrenyl group, chrysenyl group, naphthacenyl group, preadenyl group, picenyl group, perylenyl group, pentaphenyl group, pentacenyl group, tetraphenylenyl group, Examples include a hexaphenyl group, a hexacenyl group, a rubicenyl group, a coronenyl group, a trinaphthylenyl group, a heptaphenyl group, a heptacenyl group, a pyranthrenyl group, and an ovalenyl group.

  The heterocyclic group that may have a substituent is preferably an aromatic or aliphatic heterocyclic ring containing a nitrogen atom, an oxygen atom, a sulfur atom, or a phosphorus atom. For example, thienyl group, benzo [b] thienyl group, naphtho [2,3-b] thienyl group, thiantenyl group, furyl group, pyranyl group, isobenzofuranyl group, chromenyl group, xanthenyl group, phenoxathinyl group, 2H-pyrrolyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, pyridyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, indolizinyl group, isoindolyl group, 3H-indolyl group, indolyl group, 1H-indazolyl group, purinyl group, 4H- Quinolinidyl group, isoquinolyl group, quinolyl group, phthalazinyl group, naphthyridinyl group, quinoxanilyl group, quinazolinyl group, cinnolinyl group, pteridinyl group, 4aH-carbazolyl group, carbazolyl group, β-carbolinyl group, phenanthridinyl group, acridinyl group, perimidinyl group Group, phenanthrolinyl group, phenazinyl group, phenalsadinyl group, isothiazolyl group, phenothiazinyl group, isoxazolyl group, furazanyl group, phenoxazinyl group, isochromanyl group, chromanyl group, pyrrolidinyl group, pyrrolinyl group, imidazolidinyl group, imidazolinyl group, pyrazolidinyl group Group, pyrazolinyl group, piperidyl group, piperazinyl group, indolinyl group, isoindolinyl group, quinuclidinyl group, morpholinyl group, thioxanthryl group and the like.

  Furthermore, the alkyl group which may have a substituent mentioned above, the alkenyl group which may have a substituent, the alkynyl group which may have a substituent, the aryl group and the substituent which may have a substituent The hydrogen atom of the heterocyclic group which may have may be further substituted with another substituent.

  Examples of such substituents include halogen groups such as fluorine atom, chlorine atom, bromine atom and iodine atom, alkoxy groups such as methoxy group, ethoxy group and tert-butoxy group, aryl groups such as phenoxy group and p-tolyloxy group. Oxy group, methoxycarbonyl group, butoxycarbonyl group, phenoxycarbonyl group, vinyloxycarbonyl group, alkoxycarbonyl group such as aryloxycarbonyl group, acetoxy group, propionyloxy group, acyloxy group such as benzoyloxy group, acetyl group, benzoyl group , An acyl group such as an isobutyryl group, an acryloyl group, a methacryloyl group, a methoxalyl group, an alkylsulfanyl group such as a methylsulfanyl group or a tert-butylsulfanyl group, a phenylsulfanyl group, or a p-tolylsulfanyl group Alkylsulfuryl groups, methylamino groups, alkylamino groups such as cyclohexylamino groups, dimethylamino groups, diethylamino groups, morpholino groups, piperidino groups and other dialkylamino groups, phenylamino groups, p-tolylamino groups and other arylamino groups, methyl groups Alkyl groups such as ethyl group, tert-butyl group, dodecyl group, phenyl group, p-tolyl group, xylyl group, cumenyl group, naphthyl group, anthryl group, phenanthryl group and other aryl groups, hydroxyl group, carboxyl Group, sulfonamido group, formyl group, mercapto group, sulfo group, mesyl group, p-toluenesulfonyl group, amino group, nitro group, nitroso group, cyano group, trifluoromethyl group, trichloromethyl group, trimethylsilyl group, phosphinico group , Phosphono group, alkyl Ruhoniru group, an arylsulfonyl group, trialkylammonium group, dimethylsulfoxide Niu mill group, triphenyl phenacyl phosphonium Niu mill group, and the like.

  Among such substituents, a preferred substituent is an electron-withdrawing substituent. When the electron-withdrawing substituent is substituted, the ionic compound is generally easily dissociated and the antistatic ability is enhanced.

  Such electron-attracting substituents are generic names for substituents that attract electrons from the other party by resonance effects and induced effects, and many of them have a positive value for the substituent constant σ in Hammett's rule. It is. These substituents are not particularly limited, and specific examples thereof include Chemical Review Vol. 91, Nos. 165 to 195, which have a σp greater than 0 described in 1991, more specifically, a halogen group, a cyano group, a carboxyl group, a nitro group, a nitroso group, an acyl group, an alkyloxycarbonyl Group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group, trialkylammonium group, amide group, perfluoroalkyl group, perfluoroalkylthio group, perfluoroalkylcarbonyl group, sulfonamide group, 4-cyanophenyl group and the like.

R ¹ to R ⁴ are preferably an alkyl group which may have a substituent or an aryl group which may have a substituent, more preferably a substituent, in view of the stability of the compound. It is an aryl group that may have.

R ⁵ to R ⁸ are preferably an alkyl group which may have a substituent in consideration of the stability of the compound.

  Although the representative example of a compound represented by General formula (1) of this invention is specifically illustrated below as exemplary compound (7)-(86), it is not restricted to these. In the exemplified compounds, Me is a methyl group, Et is an ethyl group, Pr is a normal propyl group, i-Pr is an isopropyl group, Bu is a normal butyl group, Hex is a normal hexyl group, c-Hex is a cyclohexyl group, and Oct is Octyl group, Cet represents cetyl group, and Ph represents phenyl group.

Moreover, it is preferable to use the organic cation represented by the following general formula (3)-(6) as a cation (C) combined with the anion represented by Chemical formula (2).

[R9 in Formula (3) represents a hydrocarbon group having 4 to 20 carbon atoms, may contain a hetero atom, R10 and R11 may be the same or different, and hydrogen or a carbon atom having 1 to 12 carbon atoms. Represents a hydrogen group and may contain a heteroatom. However, when the nitrogen atom contains a double bond, there is no R3. ],
[R12 in Formula (4) represents a hydrocarbon group having 2 to 20 carbon atoms and may contain a heteroatom, and R12, R14, and R14 may be the same or different, Represents 10 hydrocarbon groups and may contain heteroatoms. ],
[R16 in Formula (5) represents a hydrocarbon group having 2 to 20 carbon atoms, and may include a heteroatom. R17, R18, and R19 may be the same or different, Represents a hydrocarbon group of 2 and may contain heteroatoms. ],
[X in Formula (6) represents a nitrogen, sulfur, or phosphorus atom, and R20, R21, R22, and R22 are the same or different and each represents a hydrocarbon group having 1 to 10 carbon atoms; May be included. However, when X is a sulfur atom, there is no R20. ].

  Examples of the cation represented by the general formula (3) include a pyridinium cation, a piperidinium cation, a pyrrolidinium cation, a cation having a pyrroline skeleton, and a cation having a pyrrole skeleton. Specific examples include 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, 1-hexyl-3. -Methylpyridinium cation, 1-butyl-3,4-dimethylpyridinium cation, 1,1-dimethylpiperidinium cation, 1-ethyl-1-methylpiperidinium cation, 1-methyl-1-propylpiperidinium cation 1-methyl-1-octylpiperidinium cation, 1-methyl-1-laurylpiperidinium cation, 1,1-dimethylpyrrolidinium cation, 1-ethyl-1-methylpyrrolidinium cation, 1-methyl -1-propylpyrrolidinium cation, 1- Til-1-octylpyrrolidinium cation, 1-methyl-1-laurylpyrrolidinium cation, 2-methyl-1-pyrroline cation, 1-ethyl-2-phenylindole cation, 1,2-dimethylindole cation, 1 -Ethylcarbazole cation.

  Examples of the cation represented by the general formula (4) include imidazolium cation, tetrahydropymidinium cation, and dihydropyrimidinium cation. Specific examples include 1,3-dimethylimidazolium cation, 1,3 -Diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazolium cation, 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl -2,3-Dimethylimidazoli Cation, 1-butyl-2,3-dimethylimidazolium cation, 1-hexyl-2,3-dimethylimidazolium cation, 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1 , 2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2, 3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,3-dimethyl-1,4-dihydropyrimidinium cation, 1,3-dimethyl-1,6-dihydropyrimidi Cation, 1,2,3-trimethyl-1,4-dihydropyrimidinium cation, 1,2,3-trimethyl-1,6-dihydropyrimidinium One, 1,2,3,4-tetramethyl-1,4-dihydropyrimidinium cation, and a 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation.

  Examples of the cation represented by the general formula (5) include a pyrazolium cation and a virazolinium cation. Specific examples include 1-methylpyrazolium cation, 3-methylpyrazolium cation, 1-ethyl-2-methylpyrazolinium cation and the like.

  Examples of the cation represented by the general formula (6) include a tetraalkylammonium cation, a trialkylsulfonium cation, a tetraalkylphosphonium cation, and a group in which a part of the alkyl group is substituted with an alkenyl group, an alkoxyl group, or an epoxy group. Etc. Specific examples include tetramethylammonium cation, tetraethylammonium cation, tetrabutylammonium cation, tetrahexylammonium cation, triethylmethylammonium cation, tributylethylammonium cation, trimethyldecylammonium cation, N, N-diethyl-N-methyl-N -(2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, N, N-dimethyl-N, N-dipropylammonium cation, N, N-dimethyl-N, N-dihexylammonium cation, N, N-dipropyl- N, N-dihexylammonium cation, trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, Silsulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecyl Examples thereof include phosphonium cations and diallyldimethylammonium cations.

  Among these, 1,1-dimethylpiperidinium cation, 1-ethyl-1-methylpiperidinium cation, 1-methyl-1-propylpiperidinium cation, 1-methyl-1-octylpiperidinium cation, 1-methyl-1-laurylpiperidinium cation, 1,1-dimethylpyrrolidinium cation, 1-ethyl-1-methylpyrrolidinium cation, 1-methyl-1-propylpyrrolidinium cation, 1-methyl- 1-octylpyrrolidinium cation, 1-methyl-1-laurylpyrrolidinium cation, 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1 -Butyl-3-methylimidazolium cation, 1-hexyl-3- Tyrimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazolium cation, 1 , 2-dimethyl-3-propylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, 1-hexyl-2,3-dimethylimidazolium A piperidium such as a cation, pyrrolidinium, and an imidazolium cation are preferably used, and an imidazolium cation is more preferably used.

  It is preferable to further mix a silane coupling agent with the optical pressure-sensitive adhesive of the present invention. The silane coupling agent is effective in improving the adhesion between the pressure-sensitive adhesive layer and the glass, and is particularly effective for preventing the pressure-sensitive adhesive film from floating, peeling, foaming, cracking and the like under high temperature and high humidity.

Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropyl. Methyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyl Methylmethoxysilane N- (2-aminoethyl) 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ- Le mercaptopropyl triethoxy silane, mercaptopropyl butyl trimethoxysilane γ- mercaptopropyl methyl dimethoxy silane, and the like.

  The silane coupling agent is preferably used in an amount of 0.01 to 2 parts by weight with respect to 100 parts by weight of the acrylic polymer. Although it can be used even if it is outside the numerical range, there is a possibility that the expected effect cannot be obtained or the physical properties are deteriorated.

  You may mix | blend an ultraviolet absorber, antioxidant, tackifying resin, a plasticizer, etc. with the optical adhesive in the range which does not inhibit the effect of this invention.

Next, the optical pressure-sensitive adhesive sheet of the present invention will be described.
The optical pressure-sensitive adhesive sheet of the present invention is characterized in that a pressure-sensitive adhesive layer made of an optical pressure-sensitive adhesive is formed on a substrate.

  As the substrate, plastic, glass or the like can be used. The substrate may be a film, sheet or plate. Moreover, you may use as a base material what was previously formed with the other layer on the base material.

  Examples of the plastic substrate include polyester, polyethylene, polypropylene, cellophane, cycloolefin, vinyl chloride, vinylidene chloride, polystyrene, polyvinyl alcohol, ethylene / vinyl alcohol copolymer, nylon, polyimide, triacetyl cellulose, polyethylene terephthalate (PET). ), Usually used plastics such as polycarbonate can be used. Among them, triacetyl cellulose and polyethylene terephthalate are preferable in terms of transparency and the like.

  Any glass substrate can be used as long as it is generally used for liquid crystal cells. Examples thereof include soda lime glass, micro sheet glass, alkali-free glass, Vycor glass, and quartz glass.

  In the present invention, as the base material, a polarizing film, a retardation film and the like obtained by imparting an optical function to the plastic base material are particularly preferable.

  The optical adhesive sheet of this invention should just have the adhesion layer formed on the base material. Therefore, a method of obtaining a pressure-sensitive adhesive sheet by applying a pressure-sensitive adhesive to a base material, drying to form a pressure-sensitive adhesive layer, and further bonding a release sheet. Alternatively, the pressure-sensitive adhesive can be applied to a release sheet, dried to form a pressure-sensitive adhesive layer, the substrates are bonded together, and the pressure-sensitive adhesive layer can be transferred onto the substrate.

For example, a coating apparatus such as a roll knife coater, a die coater, a lip coater, a roll coater, a bar coater, a gravure coater, a reverse coater, a silk screen coater, a dipping, or a blade coater can be used to form the adhesive layer.
The thickness of the adhesive layer is preferably 1 to 200 μm. If it is less than 1 μm, the adhesiveness may be insufficient, and if it exceeds 200 μm, the cost of the adhesive sheet may be too high.

The gel fraction of the adhesive layer is preferably 90% to 100%. A high degree of crosslinking of 90% or more increases the cohesive force, does not cause light leakage, and provides good processability. However, if it is 90% or less, the cohesive strength of the adhesive may be insufficient. The gel fraction was prepared by applying a pressure-sensitive adhesive to a PET base material to prepare an adhesive sheet, affixed to a weighed 300 mesh stainless steel wire mesh (weight W0), and affixed to a weighed weight W1 and a stainless steel wire mesh. The sample was refluxed in ethyl acetate for 5 hours, then dried at 100 ° C. for 1 hour and weighed, and the weight W2 was peeled off the adhesive sheet and the adhesive layer was wiped off. It can be calculated by a formula.
Gel fraction (%) = {(W2-W0-W3) / (W1-W0-W3)} × 100

Moreover, it is preferable that the storage elastic modulus in 23 degreeC is 1.0 * 10 < ⁵ > Pa-1.0 * 10 < ⁸ > Pa, and the said adhesion layer is 5.0 * 10 < ⁵ > Pa-5.0 * 10 < ⁷ >. Pa is more preferable, and 7.0 × 10 ⁵ Pa to 1.0 × 10 ⁷ Pa is particularly preferable. When the storage elastic modulus of the adhesive layer is within the above numerical range, light leakage does not occur and good workability can be realized.

On the other hand, when the storage elastic modulus is smaller than 1.0 × 10 ⁵ Pa, the cohesive force of the pressure-sensitive adhesive is insufficient, and light leakage may occur. Further, when the storage elastic modulus is larger than 1.0 × 10 ⁸ Pa, the cohesive force of the adhesive layer is excessive, and the adhesive layer is sufficiently adhered to the adherend when the optical adhesive sheet is bonded to the adherend. Otherwise, the adhesive strength may be insufficient.
The storage elastic modulus in the present invention is an adhesive layer sample having a diameter of 8 mm and a thickness of 1 to 2 mm, and a frequency of 1 Hz using a viscoelasticity tester “RDA-III” manufactured by TA Instruments Japan. This is a numerical value measured under conditions of a shear strain of 0.1π radians and a temperature of 23 ° C.

  EXAMPLES Next, although an Example of this invention is shown and it demonstrates still in detail, this invention is not limited by these. In the examples, “part” means “part by weight”, and “%” means “% by weight”. In addition, the evaluation items in Examples and the like were measured as follows.

<Measurement of molecular weight>
The weight average molecular weight of the acrylic polymer is a polystyrene-reduced weight average molecular weight determined by GPC measurement, and GPC measurement conditions are as follows.
Apparatus: Shodex GPC System-21 [manufactured by Showa Denko KK]
Column: A total of three Shodex KF-602.5 and two Shodex KF-606M (manufactured by Showa Denko KK) are connected and used.
・ Solvent: Tetrahydrofuran ・ Flow rate: 0.5 ml / min
・ Temperature: 40 ℃
Sample concentration: 0.1 wt%
Sample injection volume: 50 μl

<Measurement of non-volatile content>
About 1 g of each resin solution was weighed in a metal container, dried in an oven at 150 ° C. for 20 minutes, the residue was weighed, and the remaining rate was calculated to obtain a nonvolatile content (unit:%).

<Measurement of acid value (AV)>
About 1 g of a sample (acrylic polymer solution) is accurately weighed in a stoppered Erlenmeyer flask and dissolved by adding 100 ml of a toluene / ethanol (volume ratio: toluene / ethanol = 2/1) mixture. To this is added phenolphthalein reagent as an indicator and held for 30 seconds. Thereafter, the solution is titrated with a 0.1N alcoholic potassium hydroxide solution until the solution becomes light red.
The acid value was determined by the following formula. The acid value was a numerical value in the dry state of the acrylic polymer (unit: mgKOH / g).
Acid value (mgKOH / g) = {(5.611 × a × F) / S} / (solid content / 100)
Where S: Amount of sample collected (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)
F: Potency of 0.1N alcoholic potassium hydroxide solution

<Measurement of hydroxyl value (OHV)>
About 1 g of a sample (acrylic polymer solution) is accurately weighed in a stoppered Erlenmeyer flask and dissolved by adding 100 ml of a toluene / ethanol (volume ratio: toluene / ethanol = 2/1) mixture. Further, exactly 5 ml of an acetylating agent (a solution in which 25 g of acetic anhydride was dissolved in pyridine to make a volume of 100 ml) was added and stirred for about 1 hour. To this, phenolphthalein reagent is added as an indicator and lasts for 30 seconds. Thereafter, the solution is titrated with a 0.1N alcoholic potassium hydroxide solution until the solution becomes light red.
The hydroxyl value was determined by the following formula. The hydroxyl value was a numerical value in the dry state of the resin (unit: mgKOH / g).
Hydroxyl value (mgKOH / g) = [{(ba) × F × 28.25} / S] / (solid content / 100) + D
Where S: Amount of sample collected (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)
b: Consumption of 0.1N alcoholic potassium hydroxide solution in the empty experiment (ml)
F: Potency of 0.1N alcoholic potassium hydroxide solution
D: Acid value (mgKOH / g)

[Production Example 1]
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introducing tube, 76 parts of n-butyl acrylate, 20 parts of 2-methoxyethyl acrylate, 4 parts of acrylic acid, 122 parts of ethyl acetate, AIBN (2 , 2'-azobisisobutyronitrile) was charged, and the air in the reaction vessel was replaced with nitrogen gas, and then the reaction solution was polymerized at reflux temperature for 8 hours in a nitrogen atmosphere with stirring. The reaction was performed to obtain an acrylic polymer (A1) solution having a weight average molecular weight of 1,030,000 and a nonvolatile content of 30%. The acid value of this acrylic polymer was 31 mgKOH / g.

[Production Example 2]
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 91 parts of n-butyl acrylate, 5 parts of 2-methoxyethyl acrylate, 4 parts of acrylic acid, 122 parts of ethyl acetate, AIBN 0.01 Then, the air in the reaction vessel was replaced with nitrogen gas, and then the reaction solution was subjected to a polymerization reaction at a reflux temperature for 8 hours under a nitrogen atmosphere while stirring. The weight average molecular weight was 950,000, and the non-volatile content was 30. % Acrylic polymer (A2) solution was obtained. The acid value of this acrylic polymer was 31 mgKOH / g.

[Production Example 3]
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 46 parts of n-butyl acrylate, 50 parts of 2-methoxyethyl acrylate, 4 parts of acrylic acid, 122 parts of ethyl acetate, AIBN 0.01 Then, the air in the reaction vessel was replaced with nitrogen gas, and this reaction solution was subjected to a polymerization reaction at a reflux temperature for 8 hours under a nitrogen atmosphere with stirring. The weight average molecular weight was 1,080,000, and the non-volatile content was 30. % Acrylic polymer (A3) solution was obtained. The acid value of this acrylic polymer was 31 mgKOH / g.

[Production Example 4]
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 16 parts of n-butyl acrylate, 80 parts of 2-methoxyethyl acrylate, 4 parts of acrylic acid, 122 parts of ethyl acetate, AIBN 0.01 Then, the air in the reaction vessel was replaced with nitrogen gas, and then the reaction solution was subjected to a polymerization reaction at a reflux temperature for 8 hours under a nitrogen atmosphere while stirring. The weight average molecular weight was 1.16 million, and the non-volatile content was 30. % Acrylic polymer (A4) solution was obtained. The acid value of this acrylic polymer was 31 mgKOH / g.

[Production Example 5]
A reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube was charged with 66 parts of n-butyl acrylate, 30 parts of methyl acrylate, 4 parts of acrylic acid, 122 parts of ethyl acetate, and 0.01 part of AIBN. After replacing the air in the reaction vessel with nitrogen gas, the reaction solution was polymerized at a reflux temperature for 8 hours in a nitrogen atmosphere with stirring, and an acrylic having a weight average molecular weight of 1,100,000 and a non-volatile content of 30%. A system polymer (A5) solution was obtained. The acid value of this acrylic polymer was 31 mgKOH / g.

[Production Example 6]
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 48 parts of n-butyl acrylate, 50 parts of 2-methoxyethyl acrylate, 2 parts of acrylic acid, 122 parts of ethyl acetate, AIBN 0.01 Then, the air in the reaction vessel was replaced with nitrogen gas, and this reaction solution was subjected to a polymerization reaction at a reflux temperature for 8 hours under stirring in a nitrogen atmosphere. The weight average molecular weight was 1,30,000 and the non-volatile content was 30. % Acrylic polymer (A6) solution. The acid value of this acrylic polymer was 16 mgKOH / g.

[Production Example 7]
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 42 parts of n-butyl acrylate, 50 parts of 2-methoxyethyl acrylate, 8 parts of acrylic acid, 122 parts of ethyl acetate, AIBN 0.01 Then, the air in the reaction vessel was replaced with nitrogen gas, and then the reaction solution was subjected to a polymerization reaction at a reflux temperature for 8 hours under a nitrogen atmosphere while stirring. The weight average molecular weight was 1.1110,000, and the non-volatile content was 30. % Acrylic polymer (A7) solution. The acid value of this acrylic polymer was 62 mgKOH / g.

[Production Example 8]
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 45.9 parts of n-butyl acrylate, 50 parts of 2-methoxyethyl acrylate, 4 parts of acrylic acid, 2-hydroxyethyl acrylate 0 .1 part, 122 parts of ethyl acetate and 0.01 part of AIBN were charged, the air in the reaction vessel was replaced with nitrogen gas, and the reaction solution was subjected to a polymerization reaction for 8 hours at the reflux temperature in a nitrogen atmosphere with stirring. Thus, an acrylic polymer (A8) solution having a weight average molecular weight of 1.70 million and a nonvolatile content of 30% was obtained. The acid value of this acrylic polymer was 31 mgKOH / g, and the hydroxyl value was 0.5 mgKOH / g.

[Production Example 9]
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 45.7 parts of n-butyl acrylate, 50 parts of 2-methoxyethyl acrylate, 4 parts of acrylic acid, 2-hydroxyethyl acrylate 0 .3 parts, 122 parts of ethyl acetate and 0.01 part of AIBN were charged, and the air in the reaction vessel was replaced with nitrogen gas, and then the reaction solution was subjected to a polymerization reaction for 8 hours at the reflux temperature in a nitrogen atmosphere with stirring. Thus, an acrylic polymer (A9) solution having a weight average molecular weight of 1.08 million and a nonvolatile content of 30% was obtained. The acrylic polymer had an acid value of 31 mgKOH / g and a hydroxyl value of 1.5 mgKOH / g.

[Production Example 10]
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 45.5 parts of n-butyl acrylate, 50 parts of 2-methoxyethyl acrylate, 4 parts of acrylic acid, 2-
After charging 0.5 parts of hydroxyethyl acrylate, 122 parts of ethyl acetate and 0.01 part of AIBN, the air in the reaction vessel was replaced with nitrogen gas, and the reaction solution was stirred at a reflux temperature of 8 at a reflux temperature in a nitrogen atmosphere. A time polymerization reaction was carried out to obtain an acrylic polymer (A10) solution having a weight average molecular weight of 1.08 million and a non-volatile content of 30%. The acid value of this acrylic polymer was 31 mgKOH / g, and the hydroxyl value was 2.4 mgKOH / g.

Abbreviations for the monomers in Table 1 are shown below. BA: butyl acrylate, 2-MTA: 2-methoxyethyl atacrylate, MA: methyl acrylate, AA: acrylic acid, 2-HEA
: 2-hydroxyethyl acrylate.

[Example 1]
(Preparation of optical adhesive)
100 parts by weight of the nonvolatile content of the acrylic polymer (A1) solution, 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and 15 parts by weight of a trimethylolpropane adduct of tolylene diisocyanate as a curing agent Part was added and mixed and stirred uniformly to obtain an acrylic pressure-sensitive adhesive (1).

(Preparation of optical adhesive sheet)
The acrylic adhesive (1) is applied to one side of a silicone-treated polyethylene terephthalate film (thickness: 38 μm) [hereinafter referred to as a release film], heated at 100 ° C. for 2 minutes, and dried. Formed an adhesive layer of 25 μm.

Subsequently, the said adhesion layer was transcribe | transferred on the surface of the polarizing film, and it was left to stand in 23 degreeC-50% RH atmosphere for 7 days, reaction was advanced (aging), and the optical adhesive sheet was produced. The pressure-sensitive adhesive layer had a gel fraction of 92% and a storage elastic modulus at 23 ° C. of 1.6 × 10 ⁶ Pa.

[Example 2]
(Preparation of optical adhesive)
An acrylic pressure-sensitive adhesive (2) was prepared in the same manner as in Example 1 except that 15 parts by weight of the trimethylolpropane adduct of tolylene diisocyanate in Example 1 was changed to 30 parts by weight.

(Preparation of pressure-sensitive adhesive sheet for polarizing film)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive (2) was used. The pressure-sensitive adhesive layer had a gel fraction of 95% and a storage elastic modulus at 23 ° C. of 9.1 × 10 ⁶ Pa.

[Example 3]
(Preparation of optical adhesive)
An acrylic pressure-sensitive adhesive (3) was prepared in the same manner as in Example 1 except that 15 parts by weight of the trimethylolpropane adduct of tolylene diisocyanate in Example 1 was changed to 45 parts by weight.

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive (3) was used in place of the acrylic pressure-sensitive adhesive (1). The pressure-sensitive adhesive layer had a gel fraction of 99% and a storage elastic modulus at 23 ° C. of 7.0 × 10 ⁷ Pa.

[Example 4]
(Preparation of optical adhesive)
An acrylic pressure-sensitive adhesive (4) was prepared in the same manner as in Example 1 except that 15 parts by weight of tolylene diisocyanate trimethylolpropane adduct was changed to 8 parts by weight of tolylene diisocyanate isocyanurate.

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive (4) was used instead of the acrylic pressure-sensitive adhesive (1). The pressure-sensitive adhesive layer had a gel fraction of 92% and a storage elastic modulus at 23 ° C. of 9.5 × 10 ⁵ Pa.

[Example 5]
(Preparation of optical adhesive)
An acrylic pressure-sensitive adhesive (5) was prepared in the same manner as in Example 4 except that 8 parts by weight of the isocyanurate of tolylene diisocyanate in Example 4 was changed to 12 parts by weight.

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive (5) was used in place of the acrylic pressure-sensitive adhesive (1). The pressure-sensitive adhesive layer had a gel fraction of 95% and a storage elastic modulus at 23 ° C. of 5.2 × 10 ⁶ Pa.

[Example 6]
(Preparation of optical adhesive)
An acrylic pressure-sensitive adhesive (6) was prepared in the same manner as in Example 4 except that 8 parts by weight of the isocyanurate of tolylene diisocyanate in Example 4 was changed to 20 parts by weight.

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive (6) was used instead of the acrylic pressure-sensitive adhesive (1). The pressure-sensitive adhesive layer had a gel fraction of 99% and a storage elastic modulus at 23 ° C. of 9.0 × 10 ⁷ Pa.

[Example 7]
(Preparation of optical adhesive)
100 parts by weight of the nonvolatile content of the acrylic polymer (A2) solution, 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and 15 parts by weight of a trimethylolpropane adduct of tolylene diisocyanate as a curing agent Part was added and mixed and stirred uniformly to obtain an acrylic pressure-sensitive adhesive (7).

(Preparation of optical adhesive sheet)
An acrylic pressure-sensitive adhesive (7) was applied to one side of the release film and heated at 100 ° C. for 2 minutes to form a pressure-sensitive adhesive layer having a thickness of 25 μm after drying.

Subsequently, the said adhesion layer was transcribe | transferred on the surface of the polarizing film, and it was left to stand in 23 degreeC-50% RH atmosphere for 7 days, reaction was advanced (aging), and the optical adhesive sheet was produced. The gel fraction of the adhesive layer was 92%, and the storage elastic modulus at 23 ° C. was 1.2 × 10 ⁶ Pa.

[Example 8]
(Preparation of optical adhesive)
An acrylic pressure-sensitive adhesive (8) was prepared in the same manner as in Example 7 except that the acrylic polymer (A2) solution was changed to an acrylic polymer (A3) solution.

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 7 except that the acrylic pressure-sensitive adhesive (8) was used in place of the acrylic pressure-sensitive adhesive (7). The pressure-sensitive adhesive layer had a gel fraction of 92% and a storage elastic modulus at 23 ° C. of 2.0 × 10 ⁶ Pa.

[Example 9]
(Preparation of optical adhesive)
An acrylic pressure-sensitive adhesive (9) was prepared in the same manner as in Example 7 except that the acrylic polymer (A2) solution was changed to an acrylic polymer (A4) solution.

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 7 except that the acrylic pressure-sensitive adhesive (9) was used instead of the acrylic pressure-sensitive adhesive (7). The pressure-sensitive adhesive layer had a gel fraction of 92% and a storage elastic modulus at 23 ° C. of 1.8 × 10 ⁶ Pa.

[Example 10]
(Preparation of optical adhesive)
An acrylic pressure-sensitive adhesive (10) was prepared in the same manner as in Example 7, except that the acrylic polymer (A2) solution was changed to an acrylic polymer (A5) solution.

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 7 except that the acrylic pressure-sensitive adhesive (10) was used instead of the acrylic pressure-sensitive adhesive (7). The pressure-sensitive adhesive layer had a gel fraction of 92% and a storage elastic modulus at 23 ° C. of 5.6 × 10 ⁶ Pa.

[Example 11]
(Preparation of optical adhesive)
An acrylic pressure-sensitive adhesive (11) was prepared in the same manner as in Example 7 except that the acrylic polymer (A2) solution was changed to an acrylic polymer (A6) solution.

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 7 except that the acrylic pressure-sensitive adhesive (11) was used instead of the acrylic pressure-sensitive adhesive (7). The pressure-sensitive adhesive layer had a gel fraction of 91% and a storage elastic modulus at 23 ° C. of 1.2 × 10 ⁶ Pa.

[Example 12]
(Preparation of optical adhesive)
An acrylic pressure-sensitive adhesive (12) was prepared in the same manner as in Example 7 except that the acrylic polymer (A2) solution was changed to the acrylic polymer (A7) solution.

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 7 except that the acrylic pressure-sensitive adhesive (12) was used in place of the acrylic pressure-sensitive adhesive (7). The pressure-sensitive adhesive layer had a gel fraction of 93% and a storage elastic modulus at 23 ° C. of 3.2 × 10 ⁶ Pa.

[Example 13]
(Preparation of optical adhesive)
Acrylic pressure-sensitive adhesive (13) was prepared in the same manner as in Example 7, except that the acrylic polymer (A2) solution was changed to an acrylic polymer (A8) solution.

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 7 except that the acrylic pressure-sensitive adhesive (13) was used instead of the acrylic pressure-sensitive adhesive (7). The gel fraction of the adhesive layer was 92%, and the storage elastic modulus at 23 ° C. was 2.1 × 10 ⁶ Pa.

[Example 14]
(Preparation of optical adhesive)
An acrylic pressure-sensitive adhesive (14) was prepared in the same manner as in Example 7 except that the acrylic polymer (A2) solution was changed to an acrylic polymer (A9) solution.

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 7 except that the acrylic pressure-sensitive adhesive (14) was used in place of the acrylic pressure-sensitive adhesive (7). The pressure-sensitive adhesive layer had a gel fraction of 93% and a storage elastic modulus at 23 ° C. of 2.2 × 10 ⁶ Pa.

[Example 15]
(Preparation of optical adhesive)
An acrylic pressure-sensitive adhesive (15) was prepared in the same manner as in Example 7, except that the acrylic polymer (A2) solution was changed to an acrylic polymer (A10) solution.

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 7 except that the acrylic pressure-sensitive adhesive (15) was used instead of the acrylic pressure-sensitive adhesive (7). The gel fraction of the adhesive layer was 95%, and the storage elastic modulus at 23 ° C. was 2.5 × 10 ⁶ Pa.

[Example 16]
(Preparation of optical adhesive)
To 100 parts by weight of the non-volatile content of the acrylic polymer (A8) solution, 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane and 0.25 part by weight of acetylacetone as a silane coupling agent were added and mixed and stirred uniformly. Next, 0.25 parts by weight of aluminum tris (acetylacetonate) as a metal chelate curing agent is added and mixed and stirred uniformly. Further, 15 parts by weight of a trimethylolpropane adduct body of tolylene diisocyanate is added and mixed uniformly. The mixture was stirred to obtain an acrylic pressure-sensitive adhesive (16).

(Preparation of optical adhesive sheet)
The said acrylic adhesive (16) was apply | coated to the single side | surface of a peeling film, and it heated at 100 degreeC for 2 minute (s), and formed the adhesive layer whose thickness after drying is 25 micrometers.

Subsequently, the said adhesion layer was transcribe | transferred on the surface of the polarizing film, and it was left to stand in 23 degreeC-50% RH atmosphere for 7 days, reaction was advanced (aging), and the optical adhesive sheet was produced. The gel fraction of the adhesive layer was 97%, and the storage elastic modulus at 23 ° C. was 2.2 × 10 ⁶ Pa.

[Example 17]
(Preparation of optical adhesive)
To 100 parts by weight of the non-volatile content of the acrylic polymer (A8) solution, 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane and 0.25 part by weight of acetylacetone as a silane coupling agent were added and mixed and stirred uniformly. Next, 0.25 parts by weight of N, N, N ′, N′-tetraglycidyl-m-xylenediamine as an epoxy curing agent and 0.25 parts by weight of aluminum tris (acetylacetonate) as a metal chelate curing agent were added. The mixture was uniformly mixed and stirred, and 15 parts by weight of a trimethylolpropane adduct of tolylene diisocyanate was added as a curing agent, and the mixture was uniformly mixed and stirred to obtain an acrylic pressure-sensitive adhesive (17).

(Preparation of optical adhesive sheet)
The said acrylic adhesive (17) was apply | coated to the single side | surface of a peeling film, and it heated at 100 degreeC for 2 minute (s), and formed the adhesive layer whose thickness after drying is 25 micrometers.

Subsequently, the said adhesion layer was transcribe | transferred on the surface of the polarizing film, and it was left to stand in 23 degreeC-50% RH atmosphere for 7 days, reaction was advanced (aging), and the optical adhesive sheet was produced. The gel fraction of the adhesive layer was 99%, and the storage elastic modulus at 23 ° C. was 2.2 × 10 ⁶ Pa.

[Example 18]
(Preparation of optical adhesive)
Acrylic polymer (A8) To 100 parts by weight of the non-volatile content of the solution, 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane and 0.25 part by weight of acetylacetone as a silane coupling agent were added and mixed and stirred uniformly. Next, 0.1 part by weight of tetrabutylammonium tetrakis (pentafluorophenyl) borate as an antistatic agent (D) and N, N, N ′, N′-tetraglycidyl-m-xylenediamine as an epoxy-based curing agent 25 parts by weight, 0.25 parts by weight of aluminum tris (acetylacetonate) as a metal chelate curing agent are added and mixed uniformly and stirred, and 15 parts by weight of trimethylolpropane adduct of tolylene diisocyanate is added as a curing agent and uniform. Were mixed and stirred to obtain an acrylic pressure-sensitive adhesive (18).

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 17 except that the acrylic pressure-sensitive adhesive (18) was used in place of the acrylic pressure-sensitive adhesive (17). The pressure-sensitive adhesive layer had a gel fraction of 99%, a surface resistance value of 8.0 × 10 ¹¹ Ω / □, and a storage elastic modulus at 23 ° C. of 2.1 × 10 ⁶ Pa.

[Example 19]
(Preparation of optical adhesive)
An acrylic pressure-sensitive adhesive (19) was prepared in the same manner as in Example 18 except that 0.1 part by weight of tetrabutylammonium tetrakis (pentafluorophenyl) borate was changed to 1.0 part by weight.

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 17 except that the acrylic pressure-sensitive adhesive (19) was used in place of the acrylic pressure-sensitive adhesive (17). The pressure-sensitive adhesive layer had a gel fraction of 99%, a surface resistance value of 5.0 × 10 ¹⁰ Ω / □, and a storage elastic modulus at 23 ° C. of 1.8 × 10 ⁶ Pa.

[Example 20]
(Preparation of optical adhesive)
An acrylic pressure-sensitive adhesive (20) was prepared in the same manner as in Example 18 except that 0.1 part by weight of tetrabutylammonium tetrakis (pentafluorophenyl) borate was changed to 5.0 parts by weight.

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 17 except that the acrylic pressure-sensitive adhesive (20) was used instead of the acrylic pressure-sensitive adhesive (17). The pressure-sensitive adhesive layer had a gel fraction of 99%, a surface resistance value of 8.0 × 10 ⁹ Ω / □, and a storage elastic modulus at 23 ° C. of 1.6 × 10 ⁶ Pa.

[Example 21]
(Preparation of optical adhesive)
Acrylic polymer (A8) To 100 parts by weight of the non-volatile content of the solution, 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane and 0.25 part by weight of acetylacetone as a silane coupling agent were added and mixed and stirred uniformly. Next, 0.1 part by weight of 1-ethyl-3-methylimidazolium bisfluorosulfonylimide as an antistatic agent (E), and N, N, N ′, N′-tetraglycidyl-m-xylenediamine as an epoxy curing agent 0.25 parts by weight, 0.25 parts by weight of aluminum tris (acetylacetonate) as a metal chelate curing agent were added and mixed and stirred uniformly, and 15 parts by weight of trimethylolpropane adduct of tolylene diisocyanate was added as a curing agent. Were mixed and stirred uniformly to obtain an acrylic pressure-sensitive adhesive (21).

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 17 except that the acrylic pressure-sensitive adhesive (21) was used in place of the acrylic pressure-sensitive adhesive (17). The pressure-sensitive adhesive layer had a gel fraction of 99%, a surface resistance value of 6.0 × 10 ¹¹ Ω / □, and a storage elastic modulus at 23 ° C. of 2.1 × 10 ⁶ Pa.

[Example 22]
(Preparation of adhesive for use)
An acrylic pressure-sensitive adhesive (22) was prepared in the same manner as in Example 21, except that 0.1 part by weight of 1-ethyl-3-methylimidazolium bisfluorosulfonylimide was changed to 1.0 part by weight.

(Preparation of adhesive sheet for use)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 17 except that the acrylic pressure-sensitive adhesive (22) was used instead of the acrylic pressure-sensitive adhesive (17). The pressure-sensitive adhesive layer had a gel fraction of 99%, a surface resistance value of 3.0 × 10 ¹⁰ Ω / □, and a storage elastic modulus at 23 ° C. of 1.8 × 10 ⁶ Pa.

[Example 23]
(Preparation of optical adhesive)
An acrylic pressure-sensitive adhesive (23) was prepared in the same manner as in Example 18 except that 0.1 part by weight of 1-ethyl-3-methylimidazolium bisfluorosulfonylimide was changed to 5.0 parts by weight.

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Example 17 except that the acrylic pressure-sensitive adhesive (23) was used in place of the acrylic pressure-sensitive adhesive (17). The pressure-sensitive adhesive layer had a gel fraction of 99%, a surface resistance value of 6.0 × 10 ⁹ Ω / □, and a storage elastic modulus at 23 ° C. of 1.6 × 10 ⁶ Pa.

[Comparative Example 1]
(Preparation of optical adhesive)
A non-volatile content of 100 parts by weight of the acrylic polymer (A1) solution, 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and N, N, N ′, N′—as an epoxy curing agent 15 parts by weight of tetraglycidyl-m-xylenediamine was added, and the mixture was uniformly mixed and stirred to obtain an acrylic pressure-sensitive adhesive (21).

(Preparation of optical adhesive sheet)
The acrylic pressure-sensitive adhesive (21) was applied to one side of a release film and heated at 100 ° C. for 2 minutes to form a pressure-sensitive adhesive layer having a dry thickness of 25 μm.

Next, the pressure-sensitive adhesive layer was transferred to the surface of the polarizing film and left to stand for 7 days in an atmosphere of 23 ° C.-50% RH, and the reaction was allowed to proceed (aging) to produce an optical pressure-sensitive adhesive sheet. The pressure-sensitive adhesive layer had a gel fraction of 100% and a storage elastic modulus at 23 ° C. of 6.6 × 10 ⁵ Pa.

[Comparative Example 2]
(Preparation of optical adhesive)
To 100 parts by weight of the non-volatile content of the acrylic polymer (A1) solution, 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane and 15 parts by weight of acetylacetone are added as a silane coupling agent and mixed and stirred uniformly. Then, 15 parts by weight of aluminum tris (acetylacetonate) was added as a metal chelate curing agent, and the mixture was uniformly mixed and stirred to obtain an acrylic pressure-sensitive adhesive (22).

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Comparative Example 1 except that the acrylic pressure-sensitive adhesive (22) was used instead of the acrylic pressure-sensitive adhesive (21). The pressure-sensitive adhesive layer had a gel fraction of 99% and a storage elastic modulus at 23 ° C. of 7.0 × 10 ⁵ Pa.

[Comparative Example 3]
(Preparation of optical adhesive)
A non-volatile content of 100 parts by weight of the acrylic polymer (A1) solution, 0.1 parts by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and 3 parts by weight of a trimethylolpropane adduct of tolylene diisocyanate as a curing agent Was added and stirred uniformly to obtain an acrylic pressure-sensitive adhesive (23).

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Comparative Example 1 except that the acrylic pressure-sensitive adhesive (23) was used in place of the acrylic pressure-sensitive adhesive (21). The pressure-sensitive adhesive layer had a gel fraction of 65% and a storage elastic modulus at 23 ° C. of 8.8 × 10 ⁴ Pa.

[Comparative Example 4]
(Preparation of optical adhesive)
An acrylic pressure-sensitive adhesive (24) was prepared in the same manner as in Comparative Example 3, except that 3 parts by weight of tolylene diisocyanate trimethylolpropane adduct was changed to 80 parts by weight.

(Preparation of optical adhesive sheet)
An optical pressure-sensitive adhesive sheet was produced in the same manner as in Comparative Example 1 except that the acrylic pressure-sensitive adhesive (24) was used instead of the acrylic pressure-sensitive adhesive (21). The gel fraction of the adhesive layer was 100%, and the storage elastic modulus at 23 ° C. was 5.4 × 10 ⁸ Pa.

  Table 2 shows the results obtained by evaluating the following items for the optical pressure-sensitive adhesive sheets produced in Examples 1 to 20. Similarly, the optical pressure-sensitive adhesive sheets produced in Comparative Examples 1 to 4 were evaluated in the same manner as in the examples. The obtained results are shown in Table 3. Examples 1 to 10 are reference examples.

<Measurement of surface resistance value>
The peeled film of the optical pressure-sensitive adhesive sheet is peeled off, and the surface resistance value of the exposed pressure-sensitive adhesive layer surface is applied under a condition of 23 ° C.-50% RH using a surface resistance value measuring device (manufactured by Mitsubishi Chemical Corporation). Measurement was performed at 100 V (unit: Ω / □).

<Light leakage phenomenon>
The optical adhesive sheet is cut into a size of 80 mm in length and 150 mm in width, and pasted on both sides of an alkali-free glass plate so that the absorption axis of the polarizing film is perpendicular, and autoclaved at 50 ° C. and 0.5 MPa for 20 minutes. Went. Then, after storing at 80 ° C. for 500 hours, the temperature was returned to room temperature (about 25 ° C.), and the presence or absence of light leakage from the four corners or peripheral edges was observed. The evaluation criteria are as follows.
A: No light leakage is observed.
○: Slight light leakage is observed.
X: Light leakage is very remarkable.

<Heat resistance and moist heat resistance>
The optical pressure-sensitive adhesive sheet was cut into a size having a vertical width of 80 mm and a horizontal width of 150 mm, adhered to a non-alkali glass plate, and autoclaved at 50 ° C. and a pressure of 0.5 MPa for 20 minutes. Thereafter, it was left in an atmosphere at 80 ° C. for 500 hours (heat resistance test). Further, after the adhesive sheet and the glass were bonded in the same manner, they were left in a constant temperature and humidity chamber of 60 ° C.-90% RH for 500 hours (moisture and heat resistance test).
After standing, the temperature was returned to room temperature, and the state of the pressure-sensitive adhesive sheet that floated / peeled, foamed or cracked was observed. Foaming is a state in which relatively large bubbles are generated at the interface between the adhesive layer and the glass (other than the peripheral edge). The floating / peeling is a state where the pressure-sensitive adhesive sheet is lifted from the glass and peeled off. A crack is a state where fine bubbles having a diameter of 1 mm or less are generated in a streak-like manner at the peripheral edge of an adhesive sheet. The evaluation criteria are as follows.
○: No bubbles are generated.
Δ: Generation of slight bubbles is observed.
X: Generation | occurrence | production of a remarkable bubble is recognized.

<Processability>
An optical pressure-sensitive adhesive is applied to one side of a release film and heated at 100 ° C. for 2 minutes to form a pressure-sensitive adhesive layer having a thickness of 25 μm after drying. Next, the pressure-sensitive adhesive layer was transferred to the surface of a polyethylene terephthalate film (thickness: 38 μm), and left for 7 days (aging) in an atmosphere of 23 ° C.-50% RH to prepare a pressure-sensitive adhesive sheet. Next, this sample is cut into 100 mm × 100 mm, the release film is peeled off, bonded to a colored release paper prepared separately, and then cut into the polyester film and the adhesive layer every 20 mm from the end portion, and divided into 5 parts. . Thereafter, the adhesive layers at both ends and the center are peeled off from the colored release paper together with the polyester film, and another 100 mm × 100 mm polyester film is stacked on the polyester film covering the adhesive layer left on the colored release paper, and 60 kg / cm at 40 ° C. After applying the pressure of ² for 1 hour, the polyester film of 100 mm × 100 mm was removed. The adhesive layer left on the colored release paper was observed to protrude from the end of the polyester film. The evaluation criteria are as follows.
(Double-circle): The protrusion of the adhesion layer was not recognized from the peeling film.
○: Slight protrusion of the adhesive layer was observed from the release film.
Δ: Protrusion of the adhesive layer from the release film was clearly observed.

<Appearance (whitening)>
The pressure-sensitive adhesive was applied to one side of the release film, heated at 100 ° C. for 2 minutes, 5 minutes, and 10 minutes, and dried to observe the appearance of the pressure-sensitive adhesive layer formed by drying. The evaluation criteria are as follows.
A: Drying for 10 minutes and no whitening.
○: Whitening occurs after drying for 10 minutes, but no whitening occurs after 5 minutes.
Δ: Slightly whitening after drying for 5 minutes, but not whitening for 2 minutes.
X: Whitening occurs after drying for 2 minutes.

<Foaming during aging>
An adhesive is applied to one side of a release film and heated at 100 ° C. for 2 minutes to form an adhesive layer having a thickness of 25 μm after drying. Next, the pressure-sensitive adhesive layer was transferred to the surface of the polarizing film of the base material, and left for 7 days (aging) in an atmosphere of 23 ° C.-50% RH. The evaluation criteria are as follows.
(Double-circle): Foaming is not confirmed.
○: Slight foaming of 50 μm or less is confirmed, but there is no practical problem.
(Triangle | delta): Many foaming 50 micrometers or more is confirmed.

<Measurement of gel fraction>
A pressure-sensitive adhesive sheet prepared by applying a pressure-sensitive adhesive to a polyethylene terephthalate film was affixed to a weighed 300-mesh stainless steel wire mesh (weight W0), and a weighed weight W1 and a sample attached to the stainless steel wire mesh in ethyl acetate. It can be calculated by the following formula from the weight W2 weighed by drying at 100 ° C. for 1 hour after reflux extraction for 5 hours and the weight W3 after weighing the PET substrate from which the adhesive sheet was peeled off from the wire mesh and the adhesive layer was wiped off.
Gel fraction (%) = {(W2-W0-W3) / (W1-W0-W3)} × 100

<Measurement of storage elastic modulus (G ')>
The pressure-sensitive adhesives obtained in Examples and Comparative Examples were coated on a release film, dried and cured in an oven at 150 ° C., and an adhesive layer having a thickness of about 0.3 mm was provided. Were repeatedly pasted to a thickness of about 1.5 mm. This was aged at a temperature of 23 ° C. and a relative humidity of 50% for 1 week, punched out to 8 mm in diameter with a punch, and used as a sample for measuring the shear storage modulus. The storage modulus (G ′) was measured using a viscoelasticity tester RDA-III (manufactured by TA Instruments Japan) under conditions of a frequency of 1 Hz, a shear strain of 0.1π radians, and a temperature of 23 ° C. The unit of the storage elastic modulus (G ′) is Pa.

<Comprehensive evaluation>
The above evaluation items were comprehensively judged and evaluated according to the following evaluation criteria.
A: Δ and X do not exist, and two or more A.
○: No X, Δ within 1 and ◎ within 1.
X: One or more x, or two or more Δ.

Abbreviations in Tables 2 and 3 are as follows.
TDI / TMP: trimethylolpropane adduct of tolylene diisocyanate, TDI / nurate: isocyanurate of tolylene diisocyanate.

Claims (8)

Containing 100 parts by weight of an acrylic polymer and 5 to 50 parts by weight of an isocyanate curing agent,
The acrylic polymer is a copolymer of monomers containing 10 to 100% by weight of monomer (A) capable of forming a homopolymer having an SP value of 10 to 18 (cal / cm ³ ) ^1/2 in a total of 100% by weight of the monomer. A polymer,
The acrylic pressure-sensitive adhesive characterized in that the acrylic polymer has a hydroxyl value of 0.05 to 5 mgKOH / g. The optical pressure-sensitive adhesive according to claim 1, wherein the acrylic polymer has an acid value of 0.05 to 80 mgKOH / g. The optical pressure-sensitive adhesive according to claim 1 or 2, further comprising one or more curing agents selected from the group consisting of epoxy-based, ethyleneimine-based, metal chelate-based, and amine-based. The optical pressure-sensitive adhesive according to any one of claims 1 to 3, further comprising 0.001 to 20 parts by weight of an antistatic agent with respect to 100 parts by weight of the acrylic polymer. The antistatic agent is an antistatic agent comprising an antistatic agent (B) represented by the following general formula (1) and / or an anion and a cation (C) represented by the following chemical formula (2): The optical pressure-sensitive adhesive according to claim 4.
General formula (1)

Wherein R ^{1 to} R ⁸ are each independently a hydrogen atom, an alkyl group that may have a substituent, an alkenyl group that may have a substituent, or an alkynyl group that may have a substituent. Represents an aryl group which may have a substituent, or a heterocyclic group which may have a substituent, and R ^{5 to} R ⁸ may form a ring with adjacent substituents.
Chemical formula (2)

6. The antistatic pressure-sensitive adhesive according to claim 5, wherein the cation (C) contains one or more cations selected from the group consisting of the following general formulas (3) to (6).
General formula (3)-(6)

[R9 in Formula (3) represents a hydrocarbon group having 4 to 20 carbon atoms, may contain a hetero atom, R10 and R11 may be the same or different, and hydrogen or a carbon atom having 1 to 12 carbon atoms. Represents a hydrogen group and may contain a heteroatom. However, when the nitrogen atom contains a double bond, there is no R3. ],
[R12 in Formula (4) represents a hydrocarbon group having 2 to 20 carbon atoms and may contain a heteroatom, and R12, R14, and R14 may be the same or different, Represents 10 hydrocarbon groups and may contain heteroatoms. ],
[R16 in Formula (5) represents a hydrocarbon group having 2 to 20 carbon atoms, and may include a heteroatom. R17, R18, and R19 may be the same or different, Represents a hydrocarbon group of 2 and may contain heteroatoms. ],
[X in Formula (6) represents a nitrogen, sulfur, or phosphorus atom, and R20, R21, R22, and R22 are the same or different and each represents a hydrocarbon group having 1 to 10 carbon atoms; May be included. However, when X is a sulfur atom, there is no R20. ] An optical pressure-sensitive adhesive sheet, wherein a pressure-sensitive adhesive layer comprising the optical pressure-sensitive adhesive according to any one of claims 1 to 6 is formed on a substrate. The optical pressure-sensitive adhesive sheet according to claim 7, wherein the storage elastic modulus of the pressure-sensitive adhesive layer at 23 ° C. is 1.0 × 10 ⁵ Pa to 1.0 × 10 ⁸ Pa.